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1 package org.oddjob.arooa;
2
3 import java.io.File  ;
4 import java.io.FileInputStream ;
5 import java.io.IOException ;
6 import java.io.InputStream ;
7 import java.lang.reflect.Modifier ;
8 import java.util.Enumeration ;
9 import java.util.Hashtable ;
10 import java.util.Properties ;
11
12 import org.apache.log4j.Logger;
13
14
18 public class SimpleObjectFactory implements ObjectFactory {
19 private static final Logger logger = Logger.getLogger(SimpleObjectFactory.class);
20
21 private final ObjectFactory parent;
22
23 public SimpleObjectFactory(ObjectFactory parent) {
24 this.parent = parent;
25 }
26
27 public SimpleObjectFactory() {
28 this(null);
29 }
30
31
32
33 private final Hashtable classDefinitions = new Hashtable ();
34
35
41 public void addResource(String classDefFileName) {
42
43 Properties props = new Properties ();
44
45 try {
46 InputStream in = this.getClass().getResourceAsStream(classDefFileName);
47
48 if (in == null) {
49 throw new ArooaException("Can't load class def list");
50 }
51 props.load(in);
52 in.close();
53 }
54 catch (IOException e) {
55 throw new ArooaException("Failed to load class def list.", e);
56 }
57
58 addProperties(props);
59 }
60
61
66 public void addFile(File file) {
67
68 Properties props = new Properties ();
69
70 try {
71 InputStream in = new FileInputStream (file);
72
73 if (in == null) {
74 throw new ArooaException("Can't load class def list");
75 }
76 props.load(in);
77 in.close();
78 }
79 catch (IOException e) {
80 throw new ArooaException("Failed to load class def list.", e);
81 }
82
83 addProperties(props);
84 }
85
86
91 public void addProperties(Properties props) {
92
93 Enumeration enumeration = props.propertyNames();
94 while (enumeration.hasMoreElements()) {
95 String key = (String ) enumeration.nextElement();
96 String value = props.getProperty(key);
97 classDefinitions.put(key, value);
98 }
99 }
100
101 public void set(String key, String value) {
102 classDefinitions.put(key, value);
103 }
104
105
117
118 public static void checkTaskClass(final Class taskClass) throws ArooaException {
119
120 if (!Modifier.isPublic(taskClass.getModifiers())) {
121 final String message = taskClass + " is not public";
122 throw new ArooaException(message);
123 }
124 if (Modifier.isAbstract(taskClass.getModifiers())) {
125 final String message = taskClass + " is abstract";
126 throw new ArooaException(message);
127 }
128 try {
129 taskClass.getConstructor(null);
130 } catch (NoSuchMethodException e) {
133 final String message = "No public no-arg constructor in "
134 + taskClass;
135 throw new ArooaException(message);
136 }
137 }
138
139 public static Class loadClass(String className) {
140 Class c = null;
141 try {
142 c = Class.forName(className);
143 } catch (ClassNotFoundException e) {
144 ClassLoader cl = Thread.currentThread().getContextClassLoader();
145 try {
146 c = cl.loadClass(className);
147 } catch (ClassNotFoundException cnfe) {
148 throw new ArooaException("Could not load class " + className, cnfe);
149 } catch (NoClassDefFoundError ncdfe) {
150 throw new ArooaException("Could not load a dependent class ("
151 + ncdfe.getMessage() + ") for class " + c.getName() , ncdfe);
152 }
153 }
154
155 logger.debug("Got class [" + className + "] with classloader ["
156 + c.getClassLoader() + "]");
157 return c;
158 }
159
160 public static Object createObjectFromClass(String className)
161 throws ArooaException, IllegalAccessException ,
162 InstantiationException {
163
164 Class c = loadClass(className);
165 checkTaskClass(c);
166
167 return c.newInstance();
168 }
169
170
173 public Object createObject(String name) throws ArooaException {
174
175 String value = (String )classDefinitions.get(name);
176 if (value == null) {
177 if (parent == null) {
178 throw new ArooaException("No definition for [" + name + "]");
179 }
180 else {
181 return parent.createObject(name);
182 }
183 }
184
185 try {
186 return createObjectFromClass(value);
187 } catch (IllegalAccessException e) {
188 throw new ArooaException("Illegal access attempting to create object of class "
189 + value + " for shorthand " + name, e);
190 } catch (InstantiationException e) {
191 throw new ArooaException("InstantiationException attempting to create object of class "
192 + value + " for shorthand " + name, e);
193 }
194 }
195 }
196 |
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